Calcitropic hormone responsiveness during pregnancy.
Release of the calcitropic hormones parathyroid hormone (PTH) and calcitonin (CT) in-response to provocative stimuli was assessed in pregnant rhesus monkeys tested three times during gestation (corresponding to the end of each trimester) and again 6 weeks post partum. In the case of PTH, although basal levels were higher during pregnancy than post partum and tended to increase with advancing gestation, similar to observations in human subjects, the incremental response of the hormone to a hypocalcemic stimulus was diminished in pregnant animals and tended to lessen with advancing gestation. Basal CT levels were also increased during pregnancy but, in contrast to PTH, the incremental CT response to a provocative stimulus was generally greater during pregnancy than post partum and tended to increase with advancing gestation. The explanation of these findings may lie in differing degrees of hormone storage. These adjustments in maternal endocrine physiology regulating calcium metabolism would have the net effect of tending to preserve the maternal skeleton by protecting it from excessive resorption at times of hypocalcemia and promoting increased calcium storage during episodes of hypercalcemia.
D000818:Animals; D002116:Calcitonin / Q000378:metabolism*; D002118:Calcium / Q000502:physiology; D004492:Edetic Acid; D005260:Female; D008253:Macaca mulatta; D008954:Models, Biological; D010281:Parathyroid Hormone / Q000378:metabolism*; D011247:Pregnancy; D011270:Pregnancy, Animal
D010281:Parathyroid Hormone; D002116:Calcitonin; D004492:Edetic Acid; D002118:Calcium